Fig. 6. The poststimulus power as a percent of prestimulus power is shown for total, delta, theta, alpha, and beta power (all channels combined) at each isoflurane concentration (mean, SD). Power decreased significantly at 0.6 and 0.9 minimum alveolar concentration (MAC) for total, delta, theta, and alpha frequency ranges. At 1.1 and 1.4 MAC, no significant change occurred. *  P < 0.001 compared with prestimulus power.